Comprehensive and reliable sonographic assessment and scoring system for inflammatory lesions of the paediatric ankle.

OBJECTIVE: The clinical decision-making process in paediatric arthritis lacks an objective, reliable bedside imaging tool. The aim of this study was to develop a US scanning protocol and assess the reliability of B-mode and Doppler scoring systems for inflammatory lesions of the paediatric ankle. METHODS: As part of the Childhood Arthritis and Rheumatology Research Alliance (CARRA) US group, 19 paediatric rheumatologists through a comprehensive literature review developed a set of standardized views and scoring systems to assess inflammatory lesions of the synovial recesses as well as tendons of the paediatric ankle. Three rounds of scoring of still images were followed by one practical exercise. Agreement among raters was assessed using two-way single score intraclass correlation coefficients (ICC). RESULTS: Of the 37 initially identified views to assess the presence of ankle synovitis and tenosynovitis, nine views were chosen for each B-mode and Doppler mode semi-quantitative evaluation. Several scoring exercises and iterative modifications resulted in a final highly reliable scoring system: anterior tibiotalar joint ICC: 0.93 (95% CI 0.92, 0.94), talonavicular joint ICC: 0.86 (95% CI 0.81, 0.90), subtalar joint ICC: 0.91 (95% CI 0.88, 0.93) and tendons ICC: 0.96 (95% CI 0.95, 0.97). CONCLUSION: A comprehensive and reliable paediatric ankle US scanning protocol and scoring system for the assessment of synovitis and tenosynovitis were successfully developed. Further validation of this scoring system may allow its use as an outcome measure for both clinical and research applications.

Emergent high fatality lung disease in systemic juvenile arthritis.

OBJECTIVE: To investigate the characteristics and risk factors of a novel parenchymal lung disease (LD), increasingly detected in systemic juvenile idiopathic arthritis (sJIA). METHODS: In a multicentre retrospective study, 61 cases were investigated using physician-reported clinical information and centralised analyses of radiological, pathological and genetic data. RESULTS: LD was associated with distinctive features, including acute erythematous clubbing and a high frequency of anaphylactic reactions to the interleukin (IL)-6 inhibitor, tocilizumab. Serum ferritin elevation and/or significant lymphopaenia preceded LD detection. The most prevalent chest CT pattern was septal thickening, involving the periphery of multiple lobes ± ground-glass opacities. The predominant pathology (23 of 36) was pulmonary alveolar proteinosis and/or endogenous lipoid pneumonia (PAP/ELP), with atypical features including regional involvement and concomitant vascular changes. Apparent severe delayed drug hypersensitivity occurred in some cases. The 5-year survival was 42%. Whole exome sequencing (20 of 61) did not identify a novel monogenic defect or likely causal PAP-related or macrophage activation syndrome (MAS)-related mutations. Trisomy 21 and young sJIA onset increased LD risk. Exposure to IL-1 and IL-6 inhibitors (46 of 61) was associated with multiple LD features. By several indicators, severity of sJIA was comparable in drug-exposed subjects and published sJIA cohorts. MAS at sJIA onset was increased in the drug-exposed, but was not associated with LD features. CONCLUSIONS: A rare, life-threatening lung disease in sJIA is defined by a constellation of unusual clinical characteristics. The pathology, a PAP/ELP variant, suggests macrophage dysfunction. Inhibitor exposure may promote LD, independent of sJIA severity, in a small subset of treated patients. Treatment/prevention strategies are needed.

Recruitment of Human C1 Esterase Inhibitor Controls Complement Activation on Blood Stage Plasmodium falciparum Merozoites.

The complement system is a front-line defense system that opsonizes and lyses invading pathogens. To survive, microbes exposed to serum must evade the complement response. To achieve this, many pathogens recruit soluble human complement regulators to their surfaces and hijack their regulatory function for protection from complement activation. C1 esterase inhibitor (C1-INH) is a soluble regulator of complement activation that negatively regulates the classical and lectin pathways of complement to protect human tissue from aberrant activation. In this article, we show that Plasmodium falciparum merozoites, the invasive form of blood stage malaria parasites, actively recruit C1-INH to their surfaces when exposed to human serum. We identified PfMSP3.1, a member of the merozoite surface protein 3 family of merozoite surface proteins, as the direct interaction partner. When bound to the merozoite surface, C1-INH retains its ability to complex with and inhibit C1s, MASP1, and MASP2, the activating proteases of the complement cascade. P. falciparum merozoites that lack PfMSP3.1 showed a marked reduction in C1-INH recruitment and increased C3b deposition on their surfaces. However, these ΔPfMSP3.1 merozoites exhibit enhanced invasion of RBCs in the presence of active complement. This study characterizes an immune-evasion strategy used by malaria parasites and highlights the complex relationship between merozoites and the complement system.

Value of dedicated small-field-of-view sacroiliac versus large-field-of-view pelvic magnetic resonance imaging for evaluating pediatric sacroiliitis.

BACKGROUND: Optimized MRI parameters can be leveraged to improve signal intensity, accelerate imaging acquisition and increase resolution. Higher-resolution imaging with a small field of view (FOV) has been proposed as standard practice for investigating sacroiliac (SI) joints, but the improvement in disease detection and characterization over pelvic imaging with large FOV has not been established. OBJECTIVE: The purpose of this study was to compare dedicated MR images of the SI joints with survey imaging (large-FOV pelvic MRI) for detecting sacroiliitis. MATERIALS AND METHODS: Fifty-eight pediatric patients suspected of having sacroiliitis underwent dedicated sacroiliac joint and survey pelvic imaging at the same imaging session. We independently evaluated the small- and large-FOV image data sets for presence or absence of sacroiliitis, e.g., bone marrow edema, erosions and synovitis. We used nonparametric statistical tests to compare lesion scores for severity of inflammation. We created test characteristics for the survey pelvic images (low-resolution images of the sacroiliac joints) using dedicated sacroiliac images (small-FOV, high-resolution images) as the gold standard. RESULTS: Dedicated sacroiliac small-FOV MRI detected more sacroiliitis compared to survey pelvic imaging with large FOV (χ2=6.125, P=0.013). Readers detected significantly more features of inflammation on small- compared to large-FOV images, e.g., erosions (P=0.039), synovitis (P=0.009), sclerosis (P=0.017) and osteitis (P=0.001). Test characteristics for pelvic large-FOV imaging were sensitivity=0.76, specificity=1.00, positive predictive value = 1.00 and negative predictive value = 0.75. CONCLUSION: This study provides test characteristics for survey pelvic MRI with lower-resolution large-field-of-view images as a screening tool for detecting sacroiliitis. Pelvic screening studies with large FOV have lower sensitivity, and dedicated sacroiliac MRI with small FOV is superior in detecting sacroiliitis when compared to pelvic screening MRI.

Antibodies to Intercellular Adhesion Molecule 1-Binding Plasmodium falciparum Erythrocyte Membrane Protein 1-DBLß Are Biomarkers of Protective Immunity to Malaria in a Cohort of Young Children from Papua New Guinea.

Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) mediates parasite sequestration to the cerebral microvasculature via binding of DBLß domains to intercellular adhesion molecule 1 (ICAM1) and is associated with severe cerebral malaria. In a cohort of 187 young children from Papua New Guinea (PNG), we examined baseline levels of antibody to the ICAM1-binding PfEMP1 domain, DBLß3PF11_0521, in comparison to four control antigens, including NTS-DBLα and CIDR1 domains from another group A variant and a group B/C variant. Antibody levels for the group A antigens were strongly associated with age and exposure. Antibody responses to DBLß3PF11_0521 were associated with a 37% reduced risk of high-density clinical malaria in the follow-up period (adjusted incidence risk ratio [aIRR] = 0.63 [95% confidence interval {CI}, 0.45 to 0.88; P = 0.007]) and a 25% reduction in risk of low-density clinical malaria (aIRR = 0.75 [95% CI, 0.55 to 1.01; P = 0.06]), while there was no such association for other variants. Children who experienced severe malaria also had significantly lower levels of antibody to DBLß3PF11_0521 and the other group A domains than those that experienced nonsevere malaria. Furthermore, a subset of PNG DBLß sequences had ICAM1-binding motifs, formed a distinct phylogenetic cluster, and were similar to sequences from other areas of endemicity. PfEMP1 variants associated with these DBLß domains were enriched for DC4 and DC13 head structures implicated in endothelial protein C receptor (EPCR) binding and severe malaria, suggesting conservation of dual binding specificities. These results provide further support for the development of specific classes of PfEMP1 as vaccine candidates and as biomarkers for protective immunity against clinical P. falciparum malaria.

Multiple Plasmodium falciparum Merozoite Surface Protein 1 Complexes Mediate Merozoite Binding to Human Erythrocytes.

Successful invasion of human erythrocytes byPlasmodium falciparummerozoites is required for infection of the host and parasite survival. The early stages of invasion are mediated via merozoite surface proteins that interact with human erythrocytes. The nature of these interactions are currently not well understood, but it is known that merozoite surface protein 1 (MSP1) is critical for successful erythrocyte invasion. Here we show that the peripheral merozoite surface proteins MSP3, MSP6, MSPDBL1, MSPDBL2, and MSP7 bind directly to MSP1, but independently of each other, to form multiple forms of the MSP1 complex on the parasite surface. These complexes have overlapping functions that interact directly with human erythrocytes. We also show that targeting the p83 fragment of MSP1 using inhibitory antibodies inhibits all forms of MSP1 complexes and disrupts parasite growthin vitro.

Characterization of Inhibitors and Monoclonal Antibodies That Modulate the Interaction between Plasmodium falciparum Adhesin PfRh4 with Its Erythrocyte Receptor Complement Receptor 1.

Plasmodium falciparum parasites must invade red blood cells to survive within humans. Entry into red blood cells is governed by interactions between parasite adhesins and red blood cell receptors. Previously we identified that P. falciparum reticulocyte binding protein-like homologue 4 (PfRh4) binds to complement receptor 1 (CR1) to mediate entry of malaria parasites into human red blood cells. In this report we characterize a collection of anti-PfRh4 monoclonal antibodies and CR1 protein fragments that modulate the interaction between PfRh4 and CR1. We identify an anti-PfRh4 monoclonal that blocks PfRh4-CR1 interaction in vitro, inhibits PfRh4 binding to red blood cells, and as a result abolishes the PfRh4-CR1 invasion pathway in P. falciparum. Epitope mapping of anti-PfRh4 monoclonal antibodies identified distinct functional regions within PfRh4 involved in modulating its interaction with CR1. Furthermore, we designed a set of protein fragments based on extensive mutagenesis analyses of the PfRh4 binding site on CR1 and determined their interaction affinities using surface plasmon resonance. These CR1 protein fragments bind tightly to PfRh4 and also function as soluble inhibitors to block PfRh4 binding to red blood cells and to inhibit the PfRh4-CR1 invasion pathway. Our findings can aid future efforts in designing specific single epitope antibodies to block P. falciparum invasion via complement receptor 1.

Antibodies to the Plasmodium falciparum Proteins MSPDBL1 and MSPDBL2 Opsonize Merozoites, Inhibit Parasite Growth, and Predict Protection From Clinical Malaria.

Increasing evidence suggests that antibodies against merozoite surface proteins (MSPs) play an important role in clinical immunity to malaria. Two unusual members of the MSP-3 family, merozoite surface protein duffy binding-like (MSPDBL)1 and MSPDBL2, have been shown to be extrinsically associated to MSP-1 on the parasite surface. In addition to a secreted polymorphic antigen associated with merozoite (SPAM) domain characteristic of MSP-3 family members, they also contain Duffy binding-like (DBL) domain and were found to bind to erythrocytes, suggesting that they play a role in parasite invasion. Antibody responses to these proteins were investigated in a treatment-reinfection study conducted in an endemic area of Papua New Guinea to determine their contribution to naturally acquired immunity. Antibodies to the SPAM domains of MSPDBL1 and MSPDBL2 as well as the DBL domain of MSPDBL1 were found to be associated with protection from Plasmodium falciparum clinical episodes. Moreover, affinity-purified anti-MSPDBL1 and MSPDBL2 were found to inhibit in vitro parasite growth and had strong merozoite opsonizing capacity, suggesting that protection targeting these antigens results from ≥2 distinct effector mechanisms. Together these results indicate that MSPDBL1 and MSPDBL2 are important targets of naturally acquired immunity and might constitute potential vaccine candidates.

The merozoite surface protein 1 complex is a platform for binding to human erythrocytes by Plasmodium falciparum.

Plasmodium falciparum is the causative agent of the most severe form of malaria in humans. The merozoite, an extracellular stage of the parasite lifecycle, invades erythrocytes in which they develop. The most abundant protein on the surface of merozoites is merozoite surface protein 1 (MSP1), which consists of four processed fragments. Studies indicate that MSP1 interacts with other peripheral merozoite surface proteins to form a large complex. Successful invasion of merozoites into host erythrocytes is dependent on this protein complex; however, the identity of all components and its function remain largely unknown. We have shown that the peripheral merozoite surface proteins MSPDBL1 and MSPDBL2 are part of the large MSP1 complex. Using surface plasmon resonance, we determined the binding affinities of MSPDBL1 and MSPDBL2 to MSP1 to be in the range of 2-4 × 10(-7) m. Both proteins bound to three of the four proteolytically cleaved fragments of MSP1 (p42, p38, and p83). In addition, MSPDBL1 and MSPDBL2, but not MSP1, bound directly to human erythrocytes. This demonstrates that the MSP1 complex acts as a platform for display of MSPDBL1 and MSPDBL2 on the merozoite surface for binding to receptors on the erythrocyte and invasion.

Lotus-like effect for metal filings recovery and particle removal on heated metal surfaces using Leidenfrost water droplets.

A "lotus-like" effect is applied to demonstrate the ability of the Leidenfrost water droplets to recover Cu particles on a heated Al substrate. Cu particles on the heated surface adhere to the rim of the Leidenfrost droplets and eventually coat the droplets' surface to form an aggregation. When Fe filings are added to the Cu particles, the aggregated mixture can then be collected using a strong rare earth magnet (NdFeB) upon evaporation of the water. We also show that the Leidenfrost effect can be effectively utilized to recover both hydrophobic (dust and activated carbon) and hydrophilic (SiO2 and MgO) particles from heated Al surfaces without any topographical modification or surfactant addition. Our results show that hydrophobic and hydrophilic materials can be collected with >92% and >96% effectiveness on grooved and smooth Al surfaces, respectively. Furthermore, we observed no significant differences in the amount of material collected above the Leidenfrost point within the tested temperature range (240 °C vs. 340 °C) as well as when the Al sheet was replaced with a Cu sheet as the substrate. However, we did observe that the Leidenfrost droplets were able to collect a greater amount of material when the working liquid was water than when it was ethanol. Our findings show promise in the development of an effective precious coinage metal filings recovery technology for application in the mint industry, as well as the self-cleaning of metallic and semiconductor surfaces where manual cleaning is not amenable.

Cannabis Use Reported by Patients Receiving Primary Care in a Large Health System.

Importance: Despite the changing legal status of cannabis and the potential impact on health, few health systems routinely screen for cannabis use, and data on the epidemiology of cannabis use, and especially medical cannabis use among primary care patients, are limited. Objective: To describe the prevalence of, factors associated with, and reasons for past-3 month cannabis use reported by primary care patients. Design, Setting, and Participants: This cross-sectional study used electronic health record data from patients aged 18 years and older who had an annual wellness visit between January 2021 and May 2023 from a primary care clinic within a university-based health system in Los Angeles, California. Exposures: Factors of interest included age, race and ethnicity, sex, employment status, and neighborhood Area Deprivation Index (ADI). Main Outcomes and Measures: Cannabis use was assessed using the Alcohol Substance Involvement Screening Test (ASSIST). Patients were also asked about reasons for use, symptoms for which they used cannabis, and mode of use. Results: Among the 175 734 patients screened, the median (range) age was 47 (18-102) years; 101 657 (58.0%) were female; 25 278 (15.7%) were Asian, 21 971 (13.7%) were Hispanic, and 51 063 (31.7%) were White. Cannabis use was reported by 29 898 (17.0%), with 10 360 (34.7%) having ASSIST scores indicative of moderate to high risk for cannabis use disorder (CUD). Prevalence of cannabis use was higher among male patients than female patients (14 939 [20.0%] vs 14 916 [14.7%]) and younger patients (18-29 years, 7592 [31.0%]; ≥60 years, 4200 [8.5%]), and lower among those who lived in the most disadvantaged neighborhoods (ADI decile 9-10, 189 [13.8%]; ADI decile 1-2, 12 431 [17.4%]). The most common modes of use included edibles (18 201 [61.6%]), smoking (15 256 [51.7%]), and vaporizing (8555 [29.0%]). While 4375 patients who reported using cannabis (15.6%) did so for medical reasons only, 21 986 patients (75.7%) reported using cannabis to manage symptoms including pain (9196 [31.7%]), stress (14 542 [50.2%]), and sleep (16 221 [56.0%]). The median (IQR) number of symptoms managed was 2 (1-4), which was higher among patients who were at moderate to high risk for CUD (4 [2-6] symptoms). Conclusions and Relevance: In this study, cannabis use and risk of CUD were common, and more than three-quarters of patients who reported any cannabis use reported doing so to manage a health-related symptom. These findings suggest that integration of information regarding cannabis use for symptom management could help provide a crucial point-of-care opportunity for clinicians to understand their patients' risk for CUD.

Needs Assessment of Musculoskeletal Ultrasound Training in North American Pediatric Rheumatology Fellowship Programs.

OBJECTIVE: Musculoskeletal ultrasound (MSUS) is widely used in adult rheumatology practice for diagnosis of arthritis and procedural guidance; however, it is not yet common practice in pediatric rheumatology. MSUS is advantageous to the pediatric population because it lacks radiation and eliminates need for sedation. This study aims to assess interest in, access to, and barriers to MSUS training in pediatric rheumatology fellowship programs in North America. METHODS: A survey was developed by pediatric rheumatology providers with experience in medical and/or MSUS education and distributed via REDCap anonymously in March 2022 (Supplementary Material). Eligible participants included current and recently graduated (<1 year) pediatric rheumatology fellows at a North American program. Descriptive statistics and bivariate analyses using design-based Pearson chi-squared tests were performed. RESULTS: Overall response rate was 78% (88/113), and 75% reported some form of MSUS training during fellowship. Only 36% indicated their program had a formal MSUS curriculum. Of those with MSUS training, 23% reported adult-only MSUS education. Eighty-four percent felt MSUS would be beneficial to their career. Major barriers to MSUS training included lack of MSUS-trained faculty, lack of time, and lack of hands-on MSUS sessions. Those who had access to MSUS training were significantly more interested in MSUS than those without (P = 0.0036). CONCLUSION: This study demonstrates that North American pediatric rheumatology fellows have a strong interest in learning MSUS, but they face significant challenges in accessing MSUS training (lack of MSUS-trained faculty, time, and access to hands-on training). MSUS should be incorporated into fellowship curriculum; however, implementation remains a challenge.

Insights into Duffy binding-like domains through the crystal structure and function of the merozoite surface protein MSPDBL2 from Plasmodium falciparum.

Invasion of human red blood cells by Plasmodium falciparum involves interaction of the merozoite form through proteins on the surface coat. The erythrocyte binding-like protein family functions after initial merozoite interaction by binding via the Duffy binding-like (DBL) domain to receptors on the host red blood cell. The merozoite surface proteins DBL1 and -2 (PfMSPDBL1 and PfMSPDBL2) (PF10_0348 and PF10_0355) are extrinsically associated with the merozoite, and both have a DBL domain in each protein. We expressed and refolded recombinant DBL domains for PfMSPDBL1 and -2 and show they are functional. The red cell binding characteristics of these domains were shown to be similar to full-length forms of these proteins isolated from parasite cultures. Futhermore, metal cofactors were found to enhance the binding of both the DBL domains and the parasite-derived full-length proteins to erythrocytes, which has implications for receptor binding of other DBL-containing proteins in Plasmodium spp. We solved the structure of the erythrocyte-binding DBL domain of PfMSPDBL2 to 2.09 Å resolution and modeled that of PfMSPDBL1, revealing a canonical DBL fold consisting of a boomerang shaped α-helical core formed from three subdomains. PfMSPDBL2 is highly polymorphic, and mapping of these mutations shows they are on the surface, predominantly in the first two domains. For both PfMSPDBL proteins, polymorphic variation spares the cleft separating domains 1 and 2 from domain 3, and the groove between the two major helices of domain 3 extends beyond the cleft, indicating these regions are functionally important and are likely to be associated with the binding of a receptor on the red blood cell.

On the diversity of malaria parasites in African apes and the origin of Plasmodium falciparum from Bonobos.

The origin of Plasmodium falciparum, the etiological agent of the most dangerous forms of human malaria, remains controversial. Although investigations of homologous parasites in African Apes are crucial to resolve this issue, studies have been restricted to a chimpanzee parasite related to P. falciparum, P. reichenowi, for which a single isolate was available until very recently. Using PCR amplification, we detected Plasmodium parasites in blood samples from 18 of 91 individuals of the genus Pan, including six chimpanzees (three Pan troglodytes troglodytes, three Pan t. schweinfurthii) and twelve bonobos (Pan paniscus). We obtained sequences of the parasites' mitochondrial genomes and/or from two nuclear genes from 14 samples. In addition to P. reichenowi, three other hitherto unknown lineages were found in the chimpanzees. One is related to P. vivax and two to P. falciparum that are likely to belong to distinct species. In the bonobos we found P. falciparum parasites whose mitochondrial genomes indicated that they were distinct from those present in humans, and another parasite lineage related to P. malariae. Phylogenetic analyses based on this diverse set of Plasmodium parasites in African Apes shed new light on the evolutionary history of P. falciparum. The data suggested that P. falciparum did not originate from P. reichenowi of chimpanzees (Pan troglodytes), but rather evolved in bonobos (Pan paniscus), from which it subsequently colonized humans by a host-switch. Finally, our data and that of others indicated that chimpanzees and bonobos maintain malaria parasites, to which humans are susceptible, a factor of some relevance to the renewed efforts to eradicate malaria.

Childhood-Onset Sjögren Syndrome Presenting as Pulmonary Hemorrhage.

Primary Sjögren syndrome is an autoimmune disease characterized by inflammation of the salivary and lacrimal exocrine glands but can also present with systemic extraglandular manifestations, including pulmonary disease. Commonly described pulmonary manifestations of Sjögren syndrome include airway disease, interstitial lung disease, pulmonary arterial hypertension, and lymphoproliferative disorders. However, diffuse alveolar hemorrhage as a sequela of Sjögren syndrome has rarely been described in the adult literature and has never been described in a child. Here we report the case of an 11-year-old girl who presented with diffuse alveolar hemorrhage and was diagnosed with childhood-onset Sjögren syndrome who otherwise lacked typical clinical features, such as sicca symptoms, at the time of presentation. She was successfully treated with corticosteroids and rituximab, with sustained pulmonary remission 1 year post diagnosis. Our case highlights the heterogenous presentation of Sjögren syndrome in the pediatric population and the need for increased awareness among pediatric providers to recognize potential systemic manifestations of this disease to avoid delayed diagnosis.

Design, synthesis, and biological evaluation of new monoamine reuptake inhibitors with potential therapeutic utility in depression and pain.

Two new series of monoamine triple reuptake inhibitors (TRIs) have been discovered through scaffold homologation of our recently reported series of 3,3-disubstituted pyrrolidine TRIs. The regioisomeric 2- and 3-ketopyrrolidines demonstrated high levels of potency against all three monoamine transporters as well as good human in vitro stability, low drug-drug interaction potential and a decreased propensity for hERG channel binding. Representative compounds from these series displayed good in vivo pharmacokinetics and high monoamine receptor occupancies which are indicators of good brain penetration.

Discovery and optimization of RO-85, a novel drug-like, potent, and selective P2X3 receptor antagonist.

Despite the extensive literature describing the role of the ATP-gated P2X(3) receptors in a variety of physiological processes the potential of antagonists as therapeutic agents has been limited by the lack of drug-like selective molecules. In this paper we report the discovery and optimization of RO-85, a novel drug-like, potent and selective P2X(3) antagonist. High-throughput screening of the Roche compound collection identified a small hit series of heterocyclic amides from a large parallel synthesis library. Rapid optimization, facilitated by high-throughput synthesis, focusing on increasing potency and improving drug-likeness resulted in the discovery of RO-85.

Identification and SAR of novel diaminopyrimidines. Part 2: The discovery of RO-51, a potent and selective, dual P2X(3)/P2X(2/3) antagonist for the treatment of pain.

The purinoceptor subtypes P2X(3) and P2X(2/3) have been shown to play a pivotal role in models of various pain conditions. Identification of a potent and selective dual P2X(3)/P2X(2/3) diaminopyrimidine antagonist RO-4 prompted subsequent optimization of the template. This paper describes the SAR and optimization of the diaminopyrimidine ring and particularly the substitution of the 2-amino group. The discovery of the highly potent and drug-like dual P2X(3)/P2X(2/3) antagonist RO-51 is presented.

Identification and SAR of novel diaminopyrimidines. Part 1: The discovery of RO-4, a dual P2X(3)/P2X(2/3) antagonist for the treatment of pain.

P2X purinoceptors are ligand-gated ion channels whose endogenous ligand is ATP. Both the P2X(3) and P2X(2/3) receptor subtypes have been shown to play an important role in the regulation of sensory function and dual P2X(3)/P2X(2/3) antagonists offer significant potential for the treatment of pain. A high-throughput screen of the Roche compound collection resulted in the identification of a novel series of diaminopyrimidines; subsequent optimization resulted in the discovery of RO-4, a potent, selective and drug-like dual P2X(3)/P2X(2/3) antagonist.

Novel Ultrasound Image Acquisition Protocol and Scoring System for the Pediatric Knee.

OBJECTIVE: The use of musculoskeletal ultrasound is increasing among pediatric rheumatologists. Reliable scoring systems are needed for the objective assessment of synovitis. The aims of this study were to create a standardized and reproducible image acquisition protocol for B-mode and Doppler ultrasound of the pediatric knee, and to develop a standardized scoring system and determine its reliability for pediatric knee synovitis. METHODS: Six pediatric rheumatologists developed a set of standard views for knee assessment in children with juvenile arthritis. Subsequently, a comprehensive literature review, practical exercises, and a consensus process were performed. A scoring system for both B-mode and Doppler was then developed and assessed for reliability. Interreader reliability or agreement among a total of 16 raters was determined using 2-way single-score intraclass correlation coefficient (ICC) analysis. RESULTS: Twenty-one views to assess knee arthritis were initially identified. Following completion of practical exercises and subsequent consensus processes, 3 views in both B-mode and Doppler were selected: suprapatellar longitudinal and medial/lateral parapatellar transverse views. Several rounds of scoring and modifications resulted in a final ICC of suprapatellar view B-mode 0.89 (95% confidence interval [95% CI] 0.86-0.92) and Doppler 0.55 (95% CI 0.41-0.69), medial parapatellar view B-mode 0.76 (95% CI 0.68-0.83) and Doppler 0.75 (95% CI 0.66-0.83), and lateral parapatellar view B-mode 0.82 (95% CI 0.75-0.88) and Doppler 0.76 (95% CI 0.66-0.84). CONCLUSION: A novel B-mode and Doppler image acquisition and scoring system for assessing synovitis in the pediatric knee was successfully developed through practical exercises and a consensus process. Study results demonstrate overall good-to-excellent reliability.